Calculations and reporting
The assessors will not do any direct calculation of indicators.They will fill in a Kobo form for each species with information on Ne and/or Nc, populations maintained, numerous other characteristics, references, maps, etc. For most species the Nc, census size, will be the main data collected, rather than Ne. If Ne is estimated in the report or publication it should be reported, of course. However, assessors should not calculate Ne from Nc manually at this point- it will be calculated as follows after all data collection is complete.
After all species and populations are reported for a country, for all cases in which Nc was recorded, the colleagues involved in data analysis (see project roles spreadsheet) will then apply at least two Ne/Nc ratios to all populations in order to obtain Ne estimates from Nc- the 0.1 as a conservative default for all species, and a taxon specific one (either from that species or from a general taxa such as 0.3 for plants). We will do this in multiple ways to generate confidence bounds for reporting in the National Reports (a low and a high estimate of Ne). This will be done also in the case of multiple estimates of Nc for a population of a given species. This would result in, for example, potentially four values: low and high Nc estimates and low and high Ne/Nc ratio assumptions.
Then all Ne values (directly extracted, and calculated from Nc) will be compared to Ne 500. Every species will receive a ratio of populations above Ne 500. This will be reported as a proportion, but the original ratio (including total number of populations) can also be retained.
The country indicator value is the mean across species (a median could be used for skewed distributions). If taxonomic groups are not represented evenly (as is likely), the indicator value is the mean of each taxonomic group’s means, which would downweight taxonomic groups that are overly represented, e.g. mammals or birds. Optionally, each species can be weighted by the proportion of its geographic range in the country, from 0 to 1, to reflect national responsibility, with full weight for endemic species (REF).
The indicator is easily disaggregated to different taxonomic groups by only including species in that taxonomic category. The same can be done for different habitats, species commonness, etc.